The present invention relates to devices such as intra aortic balloon pumps (IABPs) wherein an inflatable envelope or balloon mounted on the end of a long catheter is inserted through a blood vessel to a position in the aorta where it is operated to supplement the cardiac pumping action.
The use of catheter supported balloons as devices to assist blood circulation from an ailing heart is now a well recognized medical technique. In a typical prior art construction, a manifold or handle is mounted to provide a separate fluid connection to each of an inner and an outer tube, which extend for a length of one-half to one meter from the handle. At the far ends of the tubes a balloon is mounted to be inflated by the outer tube, while the inner tube extends through the balloon to provide a lumen for sampling or administering fluids on the far (cardiac) side of the balloon. Various balloon shapes are known.
Insertion of the balloon to a site in the aorta is accomplished by first compacting the uninflated balloon, by folding, wrapping, twisting or the like, and then inserting the compacted balloon assembly through an artery using a guide wire and/or sheath to guide it past irregularities or branches in the artery. Care must be taken during insertion to avoid trauma or perforation, particularly when the balloon is passing branches or curves of the artery.
Balloons have also been designed with a curved shape to better enable the balloon to follow a curved arterial passage or to permit the balloon to remain stably positioned in a curved arterial section during pumping. An example of such a balloon is described in U.S. patent application Ser. No. 257,752 filed Oct. 14, 1988.
When intra aortic balloons (IAB) as described in application Ser. No. 257,752 are inflated within the aorta, a pressure differential along the length of the balloon develops. As a result, the cardiac (forward) end of the balloon is exposed to a higher pressure than the opposite (tail) end of the balloon. This pressure differential may cause an undesirable folding in the tail end of the balloon. The folding of the balloon reduces the lifetime and reliability of the device as it adds stress to the balloon membrane and could eventually lead to premature failure. It would be advantageous to provide an IAB which would exhibit a relatively long operational life.
It is thus an object of the invention to provide a reliable insertable arterial balloon assembly adapted to be positioned in a curved arterial passage. It is another object of the invention to provide an insertable arterial balloon assembly having a curved balloon support structure which is better able to resist the formation of fabric folds at its tail end during intra aortic balloon pumping. A further object of the invention is to provide a balloon reliable in actual use, which may also be easily compacted and prepared for insertion into the body. Other objects will be apparent to those skilled in the art upon reading the following disclosure.